SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4279-0
Inkjet printing has emerged as a viable additive manufacturing route for organic light-emitting diodes (OLEDs), offering drop-on-demand patterning, high material utilization, and compatibility with large-area flexible substrates. This review critically examines the formulation science, printhead physics, and drying kinetics that govern the quality of inkjet-printed organic layers. We analyze the rheological window required for stable jetting, typically 1–20 mPa·s viscosity and 25–45 mN/m surface tension, and the dimensionless Ohnesorge number (0.1 < Z < 1) that defines satellite-free droplet formation. The coffee-ring effect, driven by capillary flow and solvent evaporation gradients, remains the dominant failure mode for pixel non-uniformity; binary solvent systems and substrate temperature control (40–60 °C) mitigate this. We survey recent progress in printed hole-transport, emissive, and electron-transport layers, with particular attention to cross-linkable hole-transport materials that resist interlayer dissolution. Device performance metrics from printed OLEDs now reach external quantum efficiencies of 15–20% for fluorescent emitters and >25% for phosphorescent systems, with operating lifetimes (T95) exceeding 1,000 hours at 1,000 cd/m². We identify remaining bottlenecks: nozzle clogging from aggregated nanoparticles, film thickness variation across large panels, and the absence of standardized ink formulations. The review concludes with a roadmap for industrial adoption, emphasizing in-line metrology and closed-loop process control as prerequisites for yield parity with vacuum-deposited OLEDs.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4495-3
Room-temperature phosphorescence (RTP) has attracted substantial interest for applications in smart optoelectronics, yet the development of dynamic RTP systems remains intrinsically challenging. Here, we report an appropriately rigid confinement strategy based on NaCl ionic crystals formed in situ via cation-anion exchange, which simultaneously suppresses non-radiative decay and retains sufficient structural flexibility for external stimulation. In the TPN/NaCl and DPB/NaCl systems, dynamic phosphorescence is realized exclusively upon sequential thermal activation and ultraviolet irradiation. Mechanistic investigations reveal that residual water and triplet oxygen initially quench triplet excitons, and their gradual removal enables a competitive evolution between triplet-triplet annihilation (TTA) and phosphorescence pathways. This work establishes a general design principle for constructing stimulus-responsive dynamic RTP systems and resolves the long-standing conflict between rigidity and responsiveness in organic phosphorescent materials.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3520-1
Solution-processed metal halide perovskite light-emitting diodes (PeLEDs) have advanced rapidly due to high color purity, tunable emission, and low cost, with external quantum efficiencies (EQEs) surpassing 30%. However, high EQEs are typically achieved at low brightness, suffering severe efficiency roll-off at high current densities due to Auger recombination and Joule heating. Three-dimensional (3D) perovskites offer superior charge transport but suffer from low photoluminescent quantum yield (PLQY) and efficiency roll-off. The fundamental roll-off mechanism remains poorly understood. Recently, Yao and co-workers developed a molecule-in-lattice-enabled intragrain heterostructure in 3D perovskite to promote carrier confinement. Using device-level ultrafast spectroscopy, they identified hole leakage as the origin of efficiency roll-off in pure-red CsPbI3−xBrx PeLEDs. A strong bonding small molecule with multiple anchor groups was introduced to penetrate the lead halide octahedron framework, constructing wide bandgap barriers inside perovskite grains, reducing hole leakage without compromising carrier transport. This approach enabled ultrabright, highly efficient, and stable pure-red PeLEDs with extremely low efficiency roll-off. The work provides a new strategy for achieving high brightness and efficiency simultaneously, advancing PeLED technology toward practical applications in displays and lighting.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3882-y
Organic semiconductor crystals with well-defined morphologies are highly desirable for high-performance optoelectronic devices, yet precise control over their growth remains a challenge. Here, a novel donor-acceptor (D-A) molecule, TQDPT, has been successfully developed, featuring a rigid π-conjugated acceptor core composed of thiazoloquinoxaline and naphthalene, coupled with phenylphenothiazine donors. This study presents a temperature-mediated crystallization strategy for precisely controlling the morphology and carrier transport properties of TQDPT single crystals. By systematically investigating the growth kinetics across a controlled temperature range (15–35°C), we reveal a distinct transition from needle-like structures to plate-like crystals, with tunable average widths spanning from around 2.8 to 30.1 μm. This morphological evolution is driven by temperature-dependent molecular diffusion and nucleation kinetics. Significantly, the plate-like crystals grown at 25°C exhibit an order-of-magnitude enhancement in mobility compared to needle-like counterparts, while higher temperatures of 35°C yield broader crystals with improved carrier mobility and device stability. This work highlights the critical role of temperature as a pivotal parameter in the dimensional and electronic optimization of organic crystals, offering an attractive approach to optimize functional materials for advanced optoelectronics.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4099-2
Lithium (Li)-metal batteries (LMBs) are promising next-generation energy storage systems due to their high theoretical capacity (3860 mAh g−1) and low electrochemical potential (−3.04 V vs. standard hydrogen electrode). However, uncontrollable Li dendrite growth and volume fluctuations during cycling cause low Coulombic efficiency, safety hazards, and rapid capacity decay. Conventional 3D current collectors mitigate these issues by increasing surface area and providing void space, but they suffer from top-heavy deposition and underutilization of internal space. Emerging Janus/gradient anode structures, featuring asymmetric or gradient properties in lithiophilicity, conductivity, or porosity, enable bottom-up Li plating and efficient space utilization. This review systematically summarizes design principles, operational mechanisms, and recent progress in lithiophilic-lithiophobic Janus designs, conductivity-gradient frameworks, and dual-gradient configurations. These structures collectively improve Coulombic efficiency, cyclic longevity, and safety. The review concludes with future research directions, underscoring the potential of Janus/gradient anodes for high-energy-density and durable LMBs.